want to put a v-8 in my p/u for towing. friend has a 76? p/u with what he says is a 400sb so I call GM and they tell me it may be a 400 out of a 74 impalla or a 305 out of a78 camaro or monte. anyway to tell the difference visually? was told that 400s have more freezeplugs? or should i just buy the caddy down the street with the 472 and th400 and have plenty of power! going in a 87 3500 without dual wheels to replace the 292 six(no ***** but wont blow up) 4spd 4.10 rear. thanks for any input. Ken

 

if it's mainly for towing, get the caddy engine, torque monster. I'm not too comfortable on the rear gears though. the caddy will not need to generate a whole lot of rpms to make power.

 

using it mostly around town some short hauls pulling around 9-10,000# loads. just dont want to throw a ton of money at it.

 

If its a 4 bolt 400 it will have and extra freeze plug on each side

 

yeah, for pulling the 9-10k loads, go with big block power, redline should be about 5200-5500 rpm.

 

Maybe this will help a little.

I used to sell Chevys in '94-'95. The 1 ton w/454 auto and 4.10 gears in an ext cab was rated to pull 12000 lbs., 13000 in a reg cab.

I think that the BB will do much better for you. Although I have to say the redline of a BB made for pulling should fall around 4500-4800 RPM. That's what the 454 tach read in those trucks, and they usually shifted well before that if you were pulling something.

Believe it or not, in'95 you could buy a 1 ton with a 350, but in reg. cab only. The highest gear you could get was a 3.73. It was only rated to pull ~10000 lbs. Not anymore than the 3/4 ton, but you had the stability of the dual rear wheels.

So i.e., a 400 would do fine, just not as well as the BB. But it would be better in MPG when you weren't pulling. I remember a lot of guys saying they got ~8-10 MPG with the 454 whether they were pulling something or not. I would hope the 400 would do a little better than that. Of course, nothing that was anywhere near that displacement was available then, so it's hard to say. But the very few guys that bought the 350, got about 12-14 MPG not pulling, and 8-10 pulling.

AJ

 

The truck tows fine. nice and stable with no sway and stops good just doesnt like inclines and weve got plenty in N.H. I can get the 400 for 200 bucks (belongs to a buddy) and it runs good and is in a 4spd truck so it would be a clean swap the only thing i would do is all new gaskets and timing chain and clutch just dont want to end up with a 305. they want 900 for the caddy and then all the work to put it in. only get around 10mpg with th 6 so anything is probley an improvement. found a website that shows casting #s so I'll go this weekend to get those. and count the freezeplugs. Thanks for the response's any ideas are always welcome. Ken

 

I say go for the caddy, especially in hilly areas. only "major" problem should be motor mounts.

 

Any kind of a motor swap like putting a Cadillac motor into where a Chevrolet one is, involves lots of imaginaion, fabrication, and (usually) profanity; not to mention money. In your particular case, you'd have to get a different trans (bell housing pattern is different), who knows what for an exhaust, move the battery to the other side, etc. etc. etc.

If it was me, I'd see if your friend's motor is really a 400 first. Get the casting # off the block, from the bell housing flange behind the driver's side head. Check http://www.mortec.com/castnum.htm to identify the block. If it's really a stock 400, it's lame; but a set of decent heads and a real cam will make all the difference in the world.